Empirical investigation of precipitation of hexadecanoic acid from toluene/brine system: implication to naphthenic acid precipitation from crude oils

In this study precipitation of hexadecanoic acid from an idealized oil/water (toluene/brine) system was investigated. The FTIR results revealed that the acid was mainly precipitated as calcium hexadecanoate.

Experiments designed to study the effect of water cut, acid concentration, brine concentration and pH of the brine on the amount of the precipitate formed revealed that the latter increased, albeit nonlinearly, with increase in brine pH, concentration of the acid and calcium ions. Similar effect was observed with respect to water cut but with maximum amount of the precipitate formed at water cut of about 40%; below and above which relatively lower amount of the acid was precipitated irrespective of the levels of the other factors.